640635445 has 32 divisors (see below), whose sum is σ = 847584000. Its totient is φ = 462680064.

The previous prime is 640635421. The next prime is 640635467. The reversal of 640635445 is 544536046.

640635445 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 640635445 - 2²³ = 632246837 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 980739 + ... + 981391.

It is an arithmetic number, because the mean of its divisors is an integer number (26487000).

Almost surely, 2^640635445 is an apocalyptic number.

It is an amenable number.

640635445 is a deficient number, since it is larger than the sum of its proper divisors (206948555).

640635445 is a wasteful number, since it uses less digits than its factorization.

640635445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1149.

The product of its (nonzero) digits is 172800, while the sum is 37.

The square root of 640635445 is about 25310.7772500174. Note that the first 3 decimals coincide. The cubic root of 640635445 is about 862.0589951602.

The spelling of 640635445 in words is "six hundred forty million, six hundred thirty-five thousand, four hundred forty-five".